The typical workday in Spain (no matter if you are a worker or in an office) goes from 7:00/9:00 to 15:00/18:00. This is usually a 8 hours work day (a lot of unpaid extra hours are quite typical in any IT job).
Usually there are two stops before lucnh, one at the beginning of the day, usually 15 minutes to have a coffee with coworkers and another one of 15-20 minutes at midday (11:00/12:00) to have a piece of fruit or just another coffee.
At lunch there are two options, the ones that leave job at 15:00 usually eat at 15:30 - 16:00 (quite late but quite common), the rest takes an hour to have lunch (usually two dishes and dessert [a bit too much I admit]) and they are allowed to leave normally when they make 8 hours at work.
There are a lot of flexibility if you are not public facing so you can play a bit with the arriving/living time (usually you are allowed to arrive up to 10:00 in the morning).
Only people who lives really close to home (up to 10/15 minutes) goes there to have lunch with their family and they usually also take a power nap of 15 minutes more or less.
Spanish siesta is for Fridays and holidays.